PROJECT SUMMARY Cigarette smoking is the leading preventable cause of mortality and morbidity. A central contributor to the abuse liability, or addictive potential, of tobacco products is the addition of characterizing flavors. The Food and Drug Administration (FDA) has recently been afforded the authority to regulate the availability of flavored tobacco products, including e-cigarettes and menthol-flavored cigarettes. The removal of menthol-flavored cigarettes would benefit public health, however, menthol cigarette smokers may quit or switch to another product, or substitute, and little is know regarding product choices if a flavor ban were to occur or how flavor- related text and imagery on tobacco product packaging contributes to the appeal and abuse liability of tobacco products. Behavioral economic measures of demand and substitutability evaluated in the Experimental Tobacco Marketplace (ETM) in combination with eye-tracking technology are ideally suited to address these questions prior to the implementation of regulation. The ETM is used in clinical abuse liability screening and mimics an online storefront. Eye-tracking technology is a precise, objective measure of visual attention, which contributes to decision making, including product choice. The current proposal aims to simultaneously utilize the ETM and eye tracking in menthol cigarette smokers (n=179) to determine: 1) the abuse liability and level of substitutability of regular cigarettes and e-cigarettes when menthol-flavored cigarettes are removed from the marketplace, 2) the abuse liability of menthol and non-menthol cigarettes and substitutability of e-cigarettes when flavored e-cigarette availability is manipulated, and 3) the association between abuse liability and visual attention to flavored-product text and imagery. A repeated measure 2 (cigarette availability: menthol or non- menthol) X 2 (e-cigarette availability: five flavors or both tobacco and unflavored) design will be implemented to evaluate the effects of flavored tobacco product availability on abuse liability and its association with the appeal of flavor imagery and text on packaging. The proposed study aligns with the FDA priorities outlined in RFA-OD- 17-008, specifically the areas of behavior and addiction. Results from this work will inform the outcomes of future flavored tobacco product regulation and a future R01 proposal assessing a greater variety of product standards, including flavor and packaging manipulations.